Siemens SIMATIC NET CP 443-1 Advanced Manual page 64

Configuration and operation
6.1 Security recommendations
Security functions of the product
Use the options for security settings in the configuration of the product. These includes
among others:
● Protection levels
Configure access to the CPU under "Protection".
● Security function of the communication
– Enable the security functions of the CP and set up the firewall.
– Use the secure protocol variants HTTPS, FTPS, NTP (secure) and SNMPv3.
– Leave access to the Web server of the CPU (CPU configuration) and to the Web
● Logging function
Enable the function in the security configuration and check the logged events regularly for
unauthorized access.
● Protection of the passwords of program blocks
Protect the passwords that are stored for the blocks in data blocks from being viewed.
The procedure is described below.
Know-how protection of blocks (STEP 7 V5)
You can prevent the contents of data blocks (e.g. passwords) from being read out by
protecting the block with the "KNOW_HOW_PROTECT" option. Follow the steps outlined
below in STEP 7:
1. Select the DB in the block folder.
2. Open the block in the editor.
3. Close the block in the editor.
4. Generate a source from the block in the editor.
5. Select the source of the DB in the sources folder.
6. Open the source.
7. Insert an empty line in the header of the source and write "KNOW_HOW_PROTECT" in
this line.
8. Compile the source.
Result: The block is protected. You can recognize this by the padlock symbol of the DB in
the block folder.
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If you connect to public networks, you should use the firewall. Think about the services
you want to allow access to the station via public networks. By using the
"Transmission speed" of the firewall, you can restrict the possibility of flooding and
DoS attacks.
The FETCH/WRITE functionality allows you to access any data of your PLC. The
FETCH/WRITE functionality should not be used in conjunction with public networks.
server of the CP disabled.
CP 443-1 Advanced (GX30)
Manual, 03/2019, C79000-G8976-C256-05